System and method for reducing object deformation during a pulsed heating process

ABSTRACT

An approach for optimizing the thermal budget during a pulsed heating process is disclosed. A heat sink or thermal transfer plate is configured and positioned near an object, such as a semiconductor wafer, undergoing thermal treatment. The heat sink is configured to enhance the thermal transfer rate from the object so that the object is rapidly brought down from the peak temperature after an energy pulse. High thermally-conductive material may be positioned between the plate and the object. The plate may include protrusions, ribs, holes, recesses, and other discontinuities to enhance heat transfer and avoid physical damage to the object during the thermal cycle. Additionally, the optical properties of the plate may be selected to allow for temperature measurements via energy measurements from the plate, or to provide for a different thermal response to the energy pulse. The plate may also allow for pre-heating or active cooling of the wafer.

CROSS-REFERENCE TO OTHER APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/686,506, filed Jun. 1, 2005, and hereby incorporates by referencethat provisional patent application in its entirety.

BACKGROUND OF THE INVENTION

The production of semiconductor devices requires precise control ofmaterial properties. Often, the production of such devices involvescontrolled heating of semiconductor materials. For instance, during theproduction process, semiconductor wafers (and other devices) may besubjected to an ion implantation process or processes that dope thewafer with impurities. After the ions have been implanted, the crystallattice structure of the wafer is annealed by heating the wafer to ahigh temperature. Other typical processes utilizing heat treatmentinclude growth and deposition of film layers, crystallization, and phasechange processes.

However, heat treatment, especially at higher temperatures, can havemany undesirable side effects. For example, in an annealing process, thehigh temperatures may lead to an undesired diffusion of the dopantatoms, which will lead to unpredicted or unwanted semiconductorproperties. While such diffusion may occur in the course of any heattreatment process, it may be especially troublesome when a pulse ofenergy is used to heat-treat a wafer.

If the pulse of energy is delivered to the wafer surface over a timescale that is short, relative to the time that is necessary for heat todiffuse through the thickness of the substrate, then the surface of thewafer will become substantially hotter than the opposite surface. For atypical silicon wafer that is ˜775 μm thick, that is at a temperature of˜800° C., such surface heating is achieved when the energy is absorbedwithin a region that is less than 200 μm below the surface of the wafer,when the pulse is of less than ˜20 ms duration. For a large effect, theenergy should be absorbed within less than 20 μm from the surface andthe pulse typically should be less than 5 ms in duration.

Immediately after the energy from the pulse is absorbed, the heatdiffuses through the thickness of the wafer, raising the averagetemperature of the wafer as a result. This temperature rise occurs overa timescale defined by the rate of heat diffusion through the thicknessof the wafer, which is typically ˜50 ms for a wafer at 800° C. that is775 μm thick, as is typical for 300 mm diameter wafers. Hence pulsedheating produces a rather rapid rise in the temperature of the whole ofthe wafer. The subsequent evolution of the wafer temperature depends onthe nature of the heat loss from the surfaces of the wafer into thesurroundings. For example, if the back of the wafer is held in thermalcontact with a heatsink structure, heat may be conducted away to theheatsink through the gap between the wafer and the heatsink.Alternatively, if the wafer is only supported at a few locations, andthere are no cooler surfaces nearby, then heat may be lost from thesurfaces by convection or conduction into the gas ambient surroundingthe wafer, and by the emission of thermal radiation.

The rate at which heat is lost from the surface into the bulk of thewafer is typically very high, because thermal conduction within a solidis a very rapid and efficient mechanism of heat transfer. In contrast,transfer of heat from the wafer surface almost inevitably involves athermal contact resistance that impedes the conduction of heat out ofthe wafer surface into a surrounding medium, or the relativelyinefficient heat transfer mechanisms of convection or radiation. As aresult, the bulk of the wafer tends to heat up after the pulse, and thethermal exposure (sometimes referred to as thermal budget) of thedelicate structures within the wafer may be increased to an undesirableextent. Such thermal exposure may have deleterious effects such asintroducing excessive diffusion of dopant species that have beenintroduced into the wafer. As a result there is a need to identifyimproved ways of limiting the thermal exposure of the wafer.

It is often desirable to combine the pulsed heating of the wafer surfacewith a second from of heating, called background heating, that preheatsthe wafer prior to application of the energy pulse. Typically suchheating is useful because it enables the use of a lower energy pulse toachieve any desired degree of heating of the side of the wafer that isexposed to the pulsed heating process. The magnitude of the temperaturepulse associated with the pulsed heating is also reduced, which leads toreduced stress within the wafer, as well as reducing the magnitude ofany non-uniformity of heating associated with non-uniformity in thedelivery of the energy pulse to the wafer surface. An example of thelatter arises when the wafer is coated with materials that vary incomposition across the surface that is exposed to pulsed heating. Whensuch non-uniform coatings are exposed to an energy pulse, the magnitudeof the resulting temperature non-uniformity decreases as the magnitudeof the energy pulse decreases. Furthermore the ability to preheat thewafer allows the design of more sophisticated heating cycles, includingthe possibility of ramping this background temperature up to a givenvalue and then applying the surface heating energy pulse. After thepulse, the background heating can be decreased and the wafer can cool.Various approaches are described in U.S. Pat. No. 6,849,831 and U.S.Pat. No. 6,594,446.

The ability to cool the wafer rapidly after the pulse of surface heatingis clearly important for reducing the thermal exposure. Methods forlimiting thermal exposure and improving cooling are described in U.S.Pat. No. 6,594,446, U.S. Pat. No. 5,561,735, U.S. patent applicationSer. No. 10/629,400 filed Jul. 28, 2003, U.S. patent application Ser.No. 10/706,367 filed Nov. 12, 2003, U.S. patent application Ser. No.10/646,144 filed Aug. 22, 2003, and U.S. patent application Ser. No.09/527,873 filed Mar. 17, 2000.

SUMMARY OF THE INVENTION

A method of thermally treating an object includes providing an object ina thermal processing chamber and configuring a thermal transfer platesuch that the plate has a thermal mass (i.e. heat capacity) that is nogreater than about three times the thermal mass of the object. Thethermal transfer plate is positioned in close thermal communication withthe object and, after pre-heating, the object is heated by directing atleast one pulse of energy toward the object for a duration of less thanabout 1 s. The thermal transfer plate enhances heat transfer from theobject after the pulse has ceased by way of thermal conduction andallows for greater heat transfer away from the object than is availableby radiative cooling of the object alone. In certain embodiments, thethermal transfer plate has a thermal mass no greater than theapproximate thermal mass of the object.

The thermal transfer plate, also referred to as a heatsink herein, maycomprise material such as silicon, silicon carbide, silicon nitride,silicon dioxide, aluminum oxide, sapphire, quartz, aluminum nitride,boron nitride, aluminum oxynitride, graphite, carbon, diamond, yttriumaluminum garnet, or other suitable materials, including ceramics andmetals.

The object can be heated by a pulsed array of lamps, by scanning with alaser, or by other appropriate heating methodologies. The thermaltransfer plate may be positioned such that the object rests directlyupon it, or such that the plate and the surface of the object areapproximately parallel to one another and define a gap. In certainembodiments, the gap distance is less than about 0.2 mm.

The cooling of the object may be further enhanced by disposing amaterial between the thermal transfer plate and the object, the materialbeing a gas in certain embodiments. Preferably, the gas has a highthermal conductivity, and may, for example, comprise helium.

In some embodiments, different materials may be delivered into the gapsuch that the degree of thermal coupling between the object and thethermal transfer plate differs during the thermal treatment process.

The thermal transfer plate may be used for other portions of thetreatment process, such as by pre-heating the object by emitting heatfrom the thermal transfer plate as part of the pre-heating process.

The thermal transfer plate may comprise additional features, such as aplurality of holes smaller than about 2 mm in diameter, ordiscontinuities in the plate surface, such as slits, ribs, recesses,protrusions, and holes that are preferably smaller than the thermaldiffusion length associated with the treatment process in use.Furthermore, the surface of the plate can textured to further enhanceheat transfer between the plate and the object.

The thermal transfer plate may be constructed in multiple pieces orparts, and may comprise a variety of materials or combinations thereof.In certain embodiments, the plate may be constructed such that itincludes a material that undergoes a phase change at a selectedtemperature, the temperature selected to optimize heat transfer from theobject.

The treatment process can further include augmenting the cooling byactive measures, such as directing a cooling gas at the object orthermal transfer plate, either alone or in combination.

As part of the thermal treatment process, the temperature of the objectmay be monitored directly or indirectly by monitoring energy emitted,reflected, transmitted, or otherwise measured from the object and/or thethermal transfer plate. Such monitoring can include the use of opticalsensors such as pyrometers.

A system for thermal treatment of an object within a chamber isdisclosed, the system including a heating arrangement configured todirect a pulse of energy towards a surface of an object, such as asemiconductor wafer. The energy may be produced utilizing an array oflamps or a scanning energy source such as a laser. The system alsoincludes a thermal transfer plate positioned parallel to a surface ofthe object, the plate having a thermal mass no greater than about threetimes the thermal mass of the object. In other embodiments, the thermalmass, or heat capacity, of the plate is no greater than the approximatethermal mass of the object. The object may rest directly on the plate,or may be spaced apart from the plate by a defined gap; in someembodiments, the gap distance is less than about 0.2 mm.

The gap may be filled, partially or entirely, with a material selectedto enhance the thermal transfer rate between the object and the heatsink, such as a gas with a high thermal activity. Helium may be one suchgas delivered into the gap.

The system may further comprise an additional heat source configured topre-heat the object. The additional heat source can in some embodimentsbe a thermal transfer plate configured to generate and emit heat, or maycomprise a separate source which pre-heats the object indirectly via theplate.

The system can further include a measurement device or devicesconfigured to monitor the temperature of the object based on energyemitted, transmitted, reflected, or otherwise associated with the objectand/or the thermal transfer plate.

Embodiments of the method for thermal treatment of objects may beapplicable to processing semiconductor wafers using a pulsed energysource, and may achieve a specific thermal profile through selection andplacement of a heat sink or thermal transfer plate having a specifiedthermal mass and/or other defined thermal characteristics. Such a methodincludes placing a semiconductor wafer into a rapid thermal processingchamber, preheating the wafer, and subjecting the wafer to at least onepulse of energy for less than about 1 s, such that the averagetemperature of the semiconductor wafer increases by a temperaturedifference AT between the average temperature of the wafer just prior tothe pulse (T₁) and the maximum average temperature of the wafer afterthe pulse has ceased (T₂). The heat transfer from the wafer after thepulse is enhanced beyond what cooling could be achieved otherwise. Suchenhancement is obtained by placing a thermal transfer plate in closethermal communication with the wafer. The plate may be configured tohave a thermal mass no greater than approximately three times thethermal mass of the wafer, and be appropriately configured andpositioned so that the average temperature of the wafer decreases fromT₂ by at least 50% of the value of ΔT within 1.0 s.

In certain embodiments, T₁ may be about at least 600° C. and ΔT may beat least 50° C. In other embodiments, the temperature of the waferdecreases by 50% of ΔT within 0.5 s, and in still further embodimentswithin 0.3 s.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended figures, in which:

FIG. 1 illustrates a side view an exemplary processing chamber includinga thermal transfer plate;

FIG. 2 illustrates another side view of an exemplary processing chamberincluding a thermal transfer plate;

FIG. 3 illustrates a coaxial view of an exemplary thermal transferplate;

FIG. 4 illustrates a coaxial view of another exemplary thermal transferplate;

FIGS. 5 a and 5 b depict side views of still further exemplary thermaltransfer plates; and

FIGS. 6-9 depict simulated temperature profiles over time for thermalprocessing systems.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the presentinvention, one or more examples of which are illustrated in theaccompanying drawings, with like numerals representing substantiallyidentical structural elements. Each example is provided by way ofexplanation, and not as a limitation. In fact, it will be apparent tothose skilled in the art that modifications and variations can be madewithout departing from the scope or spirit of the disclosure and claims.For instance, features illustrated or described as part of oneembodiment may be used on another embodiment to yield a still furtherembodiment. Thus, it is intended that the invention disclosed hereinincludes modifications and variations as come within the scope of theappended claims and their equivalents.

Several approaches may be of interest in the context of more preciselycontrolling thermal budget during pulsed surface heating cycles. Itshould be recognized that these approaches will be useful regardless ofhow the pulsed heating is implemented, and hence the methods may be usedin combination with a wide variety of heating sources, modes ofprocessing and heating configurations. For example they can be appliedto pulsed heating with energy from lamps, lasers, other electromagneticenergy sources (e.g. RF, microwave, millimetre-wave, THz radiationsources), particle beams, gas flows, plasmas, flames, chemicalreactions, phase changes etc. They can also be applied regardless of howthe energy impinges on the surface of the wafer. For example the energymay be applied to the whole of a wafer surface, or to selected regionsof the surface. It may also be applied by scanning an energy sourceacross the wafer surface, or by exposing the wafer to a series of pulsesin localized regions. The pulse duration can range from 10⁻¹⁵ s to ˜1 s,with typical applications involving pulses with durations between 10 μsand 10 ms. The peak temperatures of the wafer surface would lie between50° C. and 2000° C., with typical applications involving processingbetween 900° C. and 1400° C.

The efficiency of heat transfer from the wafer can be increased by avariety of means. For example, if the wafer is held in close proximityto a heatsink that is maintained at a given temperature, then theconductive heat transfer between the wafer and this heatsink can beimproved by introducing a material with a high thermal conductivitybetween the wafer and the heatsink. For example, a good thermal bond canbe introduced by a metallic element or alloy. This is especially truefor materials that are soft and easily deform to fill in the spacebetween the wafer surface and the heatsink surface, thus accommodatingany surface roughness or non-planarity of either the wafer or theheatsink. Similar benefits arise from using a material that is liquid atthe temperature of interest. Improved thermal contact can also beachieved through applying pressure to the wafer or heatsink, forcingthem into more intimate contact. Such pressure may arise from mechanicalclamping, inertial forces, electrostatic clamping or by gas pressure orby a vacuum chuck.

Although these approaches may improve conductive heat transfer, theyalso introduce some problems. For example, many of the best solids orliquids that could improve heat transfer between the wafer and theheatsink, such as liquid or soft metals, may tend to react with thewafer or contaminate it with undesirable impurities. Furthermore, mostmaterials may leave some residue on the back or edges of the wafer afterprocessing, which would have to be removed in a cleaning process.Although cleaner materials may be found that leave little contaminationon the wafer, for example elastomer materials, the temperature range oftheir use may be quite restricted for some applications.

An alternative, discussed in more detail below, is to employ a gas totransfer the heat. For example, by introducing a gas of high thermalconductivity, such as a gas with a conductivity greater than about 0.1Wm⁻¹K⁻¹ into the gap, then some of the benefits of improved heattransfer can be retained. Suitable gases can include He, H₂, D₂ andmixtures thereof. Other gases, including lower thermal conductivitygases such as N₂, O₂, H₂O, D₂O, NH₃, N₂O, NO, HCl, SiH₄, Si₂H₆, GeH₄,CH₄, CF₄, C₂H₆, C₂H₂, C₂H₄, C₃H₈, CO₂, CO, NF₃, Ne, Ar, Kr and Xe, couldalso be used, for example in mixtures for controlling the thermalconductivity of the mixture or to “switch” the heat transfer conditionsand hence adjust the wafer temperature. The gases may be used to affectthe heat transfer conditions between the wafer and the plate, or betweenthe wafer and the chamber, but they can also be used to assist withprocessing the wafer. For example they can be used to assist withoxidation, nitridation, silicidation, compound formation, deposition offilms, etching, reflow, annealing, altering surface topography etc. Theycan also be used to assist with cleaning the wafer or even othercomponents in the process chamber. They can be used in mixtures,including mixtures such as O₂ and H₂ that can react to form watervapour, or mixtures that can promote deposition of films, for example bychemical vapour deposition. Small concentrations of O₂, for example,between 100 ppb and 10% may be combined with a second gas, such as N₂ orAr, in order to help to control surface reactions during hightemperature processes, for example by forming very thin oxide layers orby preventing thermal etching or dopant loss from the surface of thewafer. The gases can also be combined with chemically reactive speciesformed by delivering radiation or electromagnetic energy to theprocessing environment. For example radicals or ions may be formed by UVradiation or by generating a plasma. The gases in the chamber can be atelevated pressure (e.g. 10 atmospheres), atmospheric pressure, or atreduced pressure, e.g. down to pressures as low as 0.1 Torr. However,thermal conduction in gases becomes inefficient at pressures below ˜1Torr, and the method described here will be most effective above thispressure. The gases, their mixture and pressure can also be optimized toprovide the best mechanical damping or cushioning with regard to thethermal deformation experienced by the wafer during a pulsed heatingprocess. For example, this may be done by selecting optimal density andviscosity of the gas or gas mixture.

The heatsink itself may be made of a thermally conductive material, suchas a metal, a semiconductor or a ceramic such as SiC. A high thermalconductivity helps to even out the temperature across the surface of theheatsink, hence leading to a more uniform temperature distributionacross the wafer. It should be recognized that although we refer to a“heatsink” the heatsink may also act as a heat source for providingbackground heating as described above. In this context, the heat-sinkingaction would be more associated with absorbing the heat that wasintroduced by the pulsed heating process, which would otherwise raisethe temperature of the wafer. The heatsink can include heating elements,for example resistive heating elements, and these can be arranged inseparate independently controllable zones if it is desirable to tune thetemperature uniformity of the heatsink. Furthermore, the heatsink canalso include cooling channels if it is desired to extract large amountsof heat from the heatsink structure in a controllable way. The heatsinkcan contain both heating and cooling channels for optimal control of thetemperature pattern and the thermal response of the heatsink structure.The heatsink can also contain elements for improving the wafer support,such as a series of passages for flowing gas or drawing vacuum. The flowof gas or application of vacuum through such passages can assist withthe wafer support as needed. Furthermore, the heatsink can include anelectrostatic chuck or other clamping means.

Optimization of heat transfer out of the wafer may also be useful inother ways. One difficult problem encountered when wafers are processedby the use of energy beams scanned across the wafer surface arisesbecause of the thermal discontinuity at the edge of the wafer. Because ascanned beam inevitably generates a lateral temperature gradientparallel to the wafer surface there is always some lateral heat flow inthis direction. As a result, as the beam approaches the edge of thewafer there is a “pile up” of heat near the edge, which can result invery large temperature non-uniformity or even wafer damage. One approachto improve this is to avoid scanning to the edge of the wafer, or tomask the edge from irradiation, but these approaches can also degradeuniformity or limit the region that can be processed. Another approachis to increase the scan velocity, so that the heat flow takes on a more“one-dimensional” pattern with thermal conduction through the waferthickness dominating the heat flow. One criterion for ensuring operationin the 1-D heat flow regime is to make sure that the dwell time of thescanning beam is much smaller than the time for lateral diffusion overthe width of the beam. For a beam of width 2b, and a scan velocity of V,the dwell time is τ˜2b/V. The time taken for heat diffuse across thewidth of this beam can be estimated as ˜(2b)²/D_(w), where D_(w) is thethermal diffusivity of the wafer at the background temperature ofinterest. Hence we reach a criterion τ>>(2b)²/D_(w). This can also berecast as a criterion relating the minimum scan speed to the dwell time,V>>(D_(w)/T)^(1/2). For silicon at ˜800° C., D_(w)˜10⁻⁵ m²/s, so for aheating process with a dwell time of 1 ms, V should be greater than ˜10cm/s. The criterion can also be stated as a criterion on scan velocityfor any given beam width, V>>D_(w)/(2b). For a beam width of 10 μm, Vshould be greater than 100 cm/s, whereas for a beam width of 200 μm, Vshould be greater than 5 cm/s. We should note in this discussion thatmany beams used for processing may not have sharp edges, and may forexample have a Gaussian intensity profile. In such cases, beam width canbe defined as a region containing the majority of the energy of thebeam. For a Gaussian beam this could be the 1/e intensity width or the1/e² intensity width, for example. Although the use of relatively highscan velocities and/or beam widths approximates a 1-D heat flow pattern,there is a penalty that the use of higher scan speeds or beam widthsrequires higher beam power in order to achieve the same peak temperaturerise. This may be impractical, or it can limit the size of the regionthat can be covered in a scan. An alternative approach is to exploit theidea of enhancing heat transfer out from the wafer as discussed here.

In particular, it may be useful to enhance the heat transfer from theedge region in order to reduce the tendency for overheating near theedge of the wafer. For example, if the wafer is held on a heatsink thatalso serves to provide preheating, then the temperature distribution andheat flow in the heatsink can be tailored to enhance cooling at the edgeof the wafer in the position that the beam would otherwise causeoverheating. Another approach can involve providing better thermalcontact between the edge of the wafer and a heatsink structure locatedin close proximity with the edge of the wafer. Any of the approachesdiscussed here can be used to enhance the lateral heat transfer from thewafer edge into a heatsink structure.

One difficulty with removing heat from the edge of the wafer arises fromthe thermal expansion of the wafer. If the wafer is loaded onto aheatsink that is used for preheating the wafer will expand to a degreethat depends on the preheat temperature selected. Furthermore, there maybe variation in the diameter of wafers. A fixed heatsink structure maybe designed to fit the size expected for the wafer at the temperature ofinterest, but there is a risk that the wafer may become too large andpress against the heatsink and break. Also there is a risk that thewafer is slightly too small and does not make adequate contact with theheatsink structure, causing inadequate cooling of the edge. Theseproblems may be alleviated by using a compressible medium between theheatsink and the wafer, which can accommodate the size mismatch.Alternatively the heatsink could be spring loaded so that it maintains aconstant pressure against at least the part of the wafer where it isneeded. That part may not be the whole periphery of the wafer, sincetypically a scanning beam would not encounter the whole edge of thewafer at the same time.

We should also note that it is possible that in some cases, the reversecondition may be necessary, e.g. at locations where the heat transfercondition can cause underheating of the wafer. Such conditions may arisewhere a scan starts, because of the absence of lateral heat transfer“ahead of the scanning beam.” Such non-uniformities may be at leastpartly compensated for by adjusting the temperature or heat flowdistribution in the heatsink structure, and by employing a variabledegree of heatsink at the wafer edge as necessary.

Although such approaches may be useful when a wafer is held on aheatsink, they are more difficult to apply to the case where the waferis to be preheated or cooled at a high ramp rate, because a heatsinkstructure often may have a large thermal mass, which prevents thepossibility of very fast changes in the background heating conditions.Although it is possible to provide improved cooling in this case byvarious means described in the patent applications mentioned above, orby other means such as the use of endothermic reactions at the wafersurfaces, further improvements are desirable.

An alternative approach is to use a much smaller thermal mass plate-likeobject as a “dynamic” heatsink that is also heated with the wafer. Thewafer can sit on top of this plate, and it can either be in closeproximity to the plate, or it can be held slightly above the plate, forexample by standoffs or by a gas-cushion etc. It is not necessary thatthe plate acts as the mechanical support for the wafer, although such aconfiguration is possible.

This approach of using various heatsink plates (also referred to hereinas “thermal transfer plates”) will be described in more detail, withrespect to the issue of controlling the thermal exposure of the waferafter surface heating of one side of the wafer. In one configuration,the heatsink plate is below the wafer and the top surface of the waferis exposed to pulsed heating. If the heat transfer between the heatsinkplate and the wafer is very efficient, then heat will rapidly pass fromthe wafer into the support plate, which will tend to raise thetemperature of the heatsink plate while cooling the wafer.

FIG. 1 is a side view of an exemplary rapid thermal processing (RTP)chamber including reflective walls 10, lamps 12 a and 12 b, opticalwindows 14 a and 14 b, and wafer 16. Sensors 30 e and 30 a monitor thetemperature of the wafer and the thermal transfer plate, and maycomprise, for instance, optical pyrometers configured as known to one ofordinary skill in the art. Sensor 30 c monitors the pulse radiationincident on the wafer. Sensor 30 d monitors radiation reflected orscattered from the wafer and sensor 30 b monitors radiation transmittedby the wafer. These sensors can be photodetectors or thermal detectors.Wafer 16 is separated from thermal transfer plate 20 by a gap 19 in thisillustration, and is surrounded at least in part by edge ring 18. Theskilled artisan will recognize that the edge ring 18 may include aspectspresently disclosed in conjunction with the thermal transfer plate 20.For instance, ring 18 may contain cooling and/or heating features.

Depending on the composition of the system, gap 19 may vary in size orbe omitted entirely (i.e. when the wafer sits directly on the thermaltransfer plate). Gap 19 may be bridged partially or entirely by offsets,protrusions, or other features of the thermal transfer plate such thatcertain portions of the thermal transfer plate may be closer thanothers. Accordingly, as discussed herein, gap 19 refers generally to thedistance between the wafer and the thermal bulk of transfer plate 20.

The skilled artisan will appreciate that the RTP chambers suitable foruse with the present invention may include other additional components,such as gas flow valves, inlets, exhausts and other regulationcomponents, and controllers such as computers for monitoring andcontrolling the treatment process. For instance, as shown in FIG. 1, theRTP chamber further includes appropriate components for directing gasflow across the wafer and through the gap 19.

FIG. 2 shows a side view of a second exemplary arrangement of an RTPchamber including a thermal transfer plate 20-1 comprising gas passages22. Additionally, a gas flow/vacuum system is configured to direct gasthrough the passages 22 to and from the gap 19. The gas flow/vacuumsystem may furthermore apply a vacuum to the gap region 19 to removegas. As will be discussed in detail below, such gas may be used tomanage the thermal conductivity between the wafer and the thermaltransfer plate. FIG. 2 also illustrates a radiant energy source 12′,rather than an array of lamps, which is configured to heat the wafer 16by scanning its surface.

FIG. 3 depicts an exemplary thermal transfer plate 20-2 as viewedcoaxially, rather than from the side. Thermal transfer plate 20-2includes gas passages 22, along with stand-off features 26, which maycomprise ribs, islands, or other protrusions of material from thesurface of the plate. Additionally, recessed regions 24 are scatteredthroughout the surface of the plate, some of which surround certain gaspassages 22. Recessed regions 24 may be configured to alter cushioningeffects of gasses passing through passages 22 and into the gap 19between the thermal transfer plate and the wafer. Additionally, asdiscussed below, loading recesses or slots 25 may be configured to allowfor easier loading or unloading of wafers by allowing clearance spacefor loading apparatus, such as robotic arms.

FIG. 4 depicts another exemplary thermal transfer plate 20-3, againviewed coaxially. Plate 20-3 features gas passages 22 and a number ofstand-off features 26, in this embodiment, a plurality of ribs. Thefeatures illustrated in the plate 20-2 of FIG. 3 and the plate 20-3 asshown in FIG. 4 may be the same on both sides of the plate, or maydiffer, depending upon the thermal characteristics desired for the RTPprocess. We should also note that although the density of the holes,ribs recesses etc. is shown as fairly even in the figures, their densitycan be varied across the surface. This may be useful for varying thewafer support positions and the damping/cushioning effect of the gaslayer between the wafer and the thermal transfer plate which may beuseful to control the deformation of the wafer and the plate in responseto the pulsed heating process.

Likewise the density of rib features and protrusions can be varied. Thismay be useful for varying the degree of flexibility of the plate, forexample making a region of it more easily deformed than a second regionof it. In general we should note that the flexibility of the plate canbe optimized by selecting the material, thickness, surface coatings andconstruction (including the ribbing features and holes etc.). Varyingthe density of the plates features can also help promote thermaluniformity, for example by allowing variation in the optical propertiesacross the surface of the thermal plate, which can affect how it absorbsor radiates optical or thermal energy.

The optical properties of the plate can also be varied by applyingcoatings to all or parts of the plate's surfaces. For example, thin filmcoatings can be applied locally to a region of the plate to make ithotter or colder than a second region. Likewise, variations in thefeatures of the plate, or even the materials used in construction of theplate, across its surface can be used to locally adjust the thermal massper unit area of different regions of the plate. In the simplest case,the thermal mass per unit area is constant, and for most designs thiswould be kept similar to the thermal mass per unit area of the wafer (atypical range might be from 0.5 to 3 times the thermal mass of thewafer). However in some cases, the thermal mass may be higher in orderto absorb more heat, or lower to absorb less heat. Such variations couldbe tuned to optimize the processing uniformity. We may note that thethermal mass per unit area of a plate of a thickness D_(plate), with aspecific heat capacity C_(plate) and a density ρ_(plate) is given byρ_(plate)C_(plate)D_(plate). Hence the thermal mass per unit area can beconveniently varied (either locally or across the whole of the plate) byvarying any of these three parameters. It can also be varied by usingadditional layers or protrusions of other materials to vary theproperties, or by introducing holes or gaps that reduce the averagelocal thermal mass.

FIGS. 5 a and 5 b show side views of still further alternativeembodiments of thermal transfer plates, in this case illustrated as 20-4and 20-5, respectively. Both plates include a plurality of gas passages22, stand-off features 26, and recessed areas 24, while FIG. 5 b alsoincludes a loading recess 25. Plates 20-4 and 20-5 further includerecessed gas reservoir regions or blind holes 28, which may furtheralter the cushioning effect of the plate. Additionally, although notshown, reservoir regions 28 may be filled with a selected material andthen sealed off in order to alter the thermal response of the transferplate.

Operation of an RTP system using thermal transfer plates as discussedabove will now be discussed in conjunction with the simulatedtemperature results shown in FIGS. 6 to 9.

FIG. 6 illustrates the concept with results from a simulation of thetemperature-time cycles experienced by a wafer during a pulsed heatingprocess both with and without a heatsink plate. Curve A shows theevolution of the average wafer temperature when it is processed withoutthe plate. At the start of the heating cycle the wafer temperature isramped up to 800° C., and then the pulse of energy is applied, andimmediately after this all the heat sources are deactivated. Thetemperature profile shown does not directly show the surface heatingitself, but the step up in average temperature at the point marked Pindicates a relatively rapid rise in the average temperature that occursshortly after the pulsed heat is delivered and diffuses through thewafer thickness. In the example considered here the resulting rise inbulk temperature is 100° C., so that the wafer is at 900° C. just afterthe heat from the pulsed heating process has spread through thethickness of the wafer. After the pulsed heating, it is assumed that thewafer cools by thermal radiation.

Curve B shows the trend of the wafer temperature when a heatsink plate20 is present. In this case it was assumed that the heatsink plate hadthe same thermal properties and the same thickness as the wafer (775μm), and that the space 19 between the wafer and the heatsink plate 20was 100 μm and that it was filled with a medium with a thermalconductivity of 0.5 Wm⁻¹K⁻¹. This medium could, for example be a gaswith a fairly high thermal conductivity introduced, for example, via gaspassages 22 as shown in FIGS. 2-5, or otherwise directed into the space19. Curve C shows the temperature-time profile for the heatsink plateitself, which matches that of the wafer during the ramp up. We see fromcurve B that when the heatsink plate is present, the initial cooling ofthe wafer from 900° C. is greatly accelerated, as a result of the rapidconduction of heat from the wafer into the heatsink plate. Curve C showshow the heatsink plate temperature rises as it absorbs heat from thewafer, and then the wafer and the heatsink plate reach a commontemperature, after which point they cool at the same rate. We also seethat the radiative cooling rate of the wafer is reduced by the heatsinkplate, because the combination of the wafer and the heatsink plate hastwice the thermal mass of the wafer alone. Hence the thermal exposure isactually greater, e.g. as the wafer cools to temperatures below ˜800° C.in this example.

Despite this, the operation of the heatsink plate may still presentadvantages, because many of the undesirable processes that occur at hightemperature, such as diffusion of dopant atoms, are thermal activatedprocesses whose rate has an exponential dependence on temperature. As aresult rapid cooling at higher temperatures is often much more importantthan the cooling rate at lower temperatures.

For fast cooling of the wafer, it is important that there be efficientheat transfer from the wafer to the heatsink plate. Although some heatwill be transferred by thermal radiation, the most effective approach isto rely on thermal conduction through the medium between the wafer andthe heatsink plate. Thermal conduction is enhanced by increasing thethermal conductivity of the medium between the wafer and the heatsinkplate and by decreasing the size of the gap (19) between the two. FIG. 7illustrates the effect of varying the size of the gap 19. In this casethe medium is assumed to have a thermal conductivity of 0.5 Wm⁻¹K⁻¹ asin FIG. 6. Curve A is the temperature-time profile for a wafer without aheatsink plate, curve B is for the case where the heatsink plate is 0.1mm away from the wafer and curve C is the case where the heatsink plateis 0.2 mm away from the wafer. Curves D and E are the temperature cyclesfor the heatsink plates when they are 0.1 or 0.2 mm away from the wafer,respectively. FIG. 7 shows that although the initial cooling rate isstill enhanced when the plate is 0.2 mm from the wafer, the coolingefficiency is decreased as a result of the reduced rate of heatconduction across a larger gap.

FIG. 8 shows the effect of the choice of the thermal conductivity of themedium between the wafer and the heatsink plate. Curves A, B, and D arethe same as for FIG. 7. Curves C and E are the wafer and plate heatingcycles respectively, for the case where the medium between the wafer andthe plate has a thermal conductivity of only 0.05 Wm⁻¹K⁻¹. In thiscomparison we see that introducing the heatsink plate has slowed downthe cooling rate. In order to use the heatsink plate concept in a mediumwith such a low thermal conductivity, the plate would have to be broughtmuch closer to the wafer in order to increase the conductive coupling.

The degree of thermal exposure experienced by the wafer will also beaffected by the properties of the heatsink plate. If the heatsink plateis made very thin or of low heat capacity, then it cannot absorb much ofthe extra heat introduced into the wafer by the pulsed heating and itdoes little to limit the temperature experienced in the wafer. FIG. 9illustrates the issue by showing the behaviour for a case where theheatsink plate was chosen to be 100 μm thick. Curves A, B and D are thesame as for FIGS. 7 & 8. Curve C is the wafer response with the heatsinkplate present, and curve E is the corresponding response of the plateitself Introducing the plate has provided a small improvement in theinitial cooling rate, but the cooling rate becomes lower than that of awafer alone once the temperature has dropped below ˜830° C. The loss ofcooling efficiency arises because the thin heatsink plate heats up veryrapidly as heat transfers to it, as shown in curve E.

Although the initial cooling rate can be enhanced by using a thickheatsink plate or one with a large heat capacity, the ability to rampthe wafer up and down in temperature becomes limited, because of thelarge thermal mass of the heatsink plate. In practice it may be usefulto accelerate the cooling rate of the wafer and the plate above thatwhich is possible by radiation cooling alone. For example, a flow of gasdirected at the wafer and/or at the thermal transfer plate can increasethe rate of heat loss above that of radiation cooling alone. This gasflow can be applied throughout the whole heating cycle, or it can beinitiated in timed relation to the preheating or pulsed heating steps.The gas cooling can be applied by increasing the rate at which gas flowsinto the chamber, or by flowing a gas that impinges directly on thesurface of the wafer and/or on the heat transfer plate. For example ashowerhead arrangement or an array of gas pipes can be used to directgas cooling at the surfaces of the wafer and/or the thermal transferplate. Alternative cooling mechanisms can also be used for coolingeither the wafer or the heat transfer plate. For example, the coolingcan be with a flow of a liquid, or a medium that experiences a phasechange or an endothermic chemical reaction that can absorb thermalenergy from the heat transfer plate or the wafer. In some cases suchcooling may be more easily applied to the thermal heat transfer platethan the wafer, because the wafers surfaces must be kept very clean anduncontaminated with foreign materials. The heat transfer plate can alsobe designed to accommodate such cooling features that increase the rateof heat transfer from it and hence accelerate its cooling. The fact thatthe wafer and the heat transfer plate are in close thermal communicationmeans that if the heat transfer plate can be cooled rapidly, then it inturn will cool the wafer rapidly. The heat transfer plate can even haveconnections that directly couple the flow of cooling media to itssurfaces or its interior. For example it can have cooling channelswithin it. It can also have electrical connections if desired, which maypermit the use of thermoelectric cooling methods. Such connections wouldalso allow for including electrical temperature sensors such asthermocouples or temperature sensitive resistors. The various featuresof the heat transfer plate, such as the ribs described above can also beused to enhance its heat loss, for example by acting as cooling finswhich increase the surface area available to dissipate heat. They canalso increase the thermal emissivity and emitting area to increase therate of radiation heat loss.

In general the thickness or heat capacity of the heatsink plate can beoptimized with respect to the type of thermal cycle that is desired. Thenature of the optimal thermal cycle will generally depend on thekinetics of the physical phenomena taking place during the thermalprocessing. An extra degree of optimization is possible by controllingthe rate of heat transfer between the wafer and the heatsink plate, forexample by controlling the gap between the two and the nature of the gasambient between the two.

In some embodiments, it is not necessary for the heatsink plate to beramped to the same temperature as the wafer before the pulsed heating isapplied. Indeed, the rate of heat loss from the wafer can be increasedby keeping the heatsink plate at a relatively low temperature comparedto the wafer. This may help in reducing the need for close physicalproximity between the wafer and the heatsink plate and the need for ahigh thermal conductivity medium between the two. For instance, acooling gas may be directed toward or through the heatsink structure,such as via channels 22. Alternatively, the heatsink may includeseparate internal channels linked to a cooling system, such as the typeof structure used in water-cooled lamps and the like. One complicationwith such approaches is that it may require separate control of thetemperature of the wafer and the heatsink plate, for example bymeasuring their temperatures with pyrometers and controlling the heatingand cooling sources accordingly.

If desired, the radiative properties of the heatsink plate can beoptimized to ensure a different thermal response to that of the wafer.For example, the emissivity or absorptivity of the heatsink plate can beoptimized to be greater or smaller than those for the wafer as desired.As noted previously, one approach for ensuring a different thermalresponse between the wafer and the plate can involve including amaterial within the heatsink plate that undergoes a phase change at apredetermined temperature in such a volume that it pins the temperatureof the heatsink plate at that predetermined temperature. For instance,such a material could be sealed within reservoirs 28 of the heatsinkstructure, or could be otherwise incorporated into a chamber or otherinternal structure. Application of more heating to the plate would thenmerely drive the phase change while the plate temperature remainedconstant. This approach reduces the demands on the control system.

One advantage of using a configuration where the wafer and the heatsinkplate are in close thermal contact is that the heatsink plate can alsoserve as a susceptor plate. If the thermal coupling between the waferand the heatsink plate is strong enough, then the temperature of theheatsink plate can be used as an indicator of the wafer temperature.This may simplify the temperature measurement approach used for controlof the process temperature. For example wafer back surfaces are oftencoated with films that affect their emissivity. As a result of this,pyrometric measurements of wafer temperature are often prone to errorunless extensive precautions are taken to correct for emissivityvariations. Since the heatsink plate can be made of a known materialwith a well characterized emissivity, it is possible to measure itstemperature accurately with a pyrometer. If the thermal coupling betweenthe wafer and the heatsink plate is such that only a small temperaturedifference can emerge between them during the period before the pulsedheating is applied, then the wafer temperature can also be closelycontrolled in this part of the heating cycle. This approach provides asimple approach for very repeatable preheating of the wafer. Even if thethermal coupling between the thermal transfer plate and the wafer is notperfect, it is possible to deduce the wafer temperature by measuring thetemperature of the thermal transfer plate and then estimating the wafertemperature from a thermal model. This model can take account of thedegree of thermal contact between the wafer and the thermal transferplate, the nature of the medium between the wafer and the plate, and theoptical or thermal energy entering or leaving the surfaces of the waferand the thermal transfer plate. Estimates of the optical energy enteringor leaving the wafer can be made more accurate through the use ofmeasurements from sensors such as 30 b, 30 c and 30 d.

An alternative approach for ensuring that the heatsink plate and thewafer are at similar temperatures is through the use of dual sidedillumination, such as illustrated in FIG. 1. If the heatsink plate andthe wafer have similar thermal masses then when they are illuminatedwith similar power densities from a dual sided heating system they willtend to follow similar thermal cycles. Lamps 12 b may be controlled topre-heat the wafer and thermal transfer plate. This preheating can alsobe combined with delivery of energy from lamps 12 a. Then, a heat pulsemay be provided using lamps 12 a or another appropriate energy source. Acombination of dual sided illumination and close thermal contact willprovide even closer tracking of the temperatures of the wafer and theheatsink plate up until the pulsed heating is applied to the wafer.

One difficulty with the use of a heatsink plate arises from the need toload the wafer onto it. Close physical proximity prevents the use of awafer loading mechanism that requires access between the plate and thewafer. The wafer could be loaded onto the plate through the use of a setof pins that pass through holes in the heatsink plate 20. The wafer alsocan be loaded onto the plate directly if the wafer is held at its edgeswith a mechanism that allows the wafer to be positioned over the plateand then lowered onto it. The heatsink plate could be adapted tofacilitate such a mechanism, such as via the loading recesses or slots25 illustrated in FIGS. 3 and 5 b. The wafer could also be supported byan approach that holds it from above, such as a Bernoulli pick-upapproach. Another approach can include loading the wafer onto asupporting element that holds the wafer near its edges and then bringingthe heatsink plate into close proximity with the wafer. The componentthat the wafer sits on can be very thin, so that it fits between theheatsink plate and the wafer. Alternatively the heatsink plate can havecut out sections so that it doesn't interfere with the wafer support.

An alternative approach is to make the heatsink plate out of more thanone part, so that it can be “pieced together” after the wafer is loadedonto part of it. For example, one part of the heatsink plate may havefeatures for supporting the wafer at defined locations, such as theislands and ribs generally denoted as protrusions 26 in FIGS. 2-5. Theprotrusions can be designed to not interfere with the wafer loadingmechanism. Once the wafer is loaded onto the supporting portion of theheatsink plate, the second part of the heatsink plate (and any furtherparts) can be put in place to complete the heatsink assembly.

Another difficulty may arise when unloading the wafer from the heatsinkplate after processing as a result of the tendency of the wafer and theplate to “stick together” because of the relatively small gap betweenthem, which impedes the flow of gas that is necessary to pull themapart. This problem may be alleviated by maintaining sufficient gapbetween the two, but that approach may compromise the coolingefficiency. Another approach would be to provide a series of holes inthe heatsink plate which allow gas to flow through it, such as gas flowpassages 22 and recessed areas 24 as shown in FIGS. 2-5. However, thenumber and size of the holes should be small enough to not affect thetemperature uniformity on the wafer during the heating cycle. This ispossible if the size of the holes is kept small enough that thermaldiffusion can even out any temperature non-uniformity that tends toarise in the wafer, for example as a result of uneven heat transfer tothe heatsink plate in the vicinity of the holes. This criterion can bemet by making the hole size of approximately 2 mm or smaller, preferablyless than 1 mm in size. The best uniformity can be achieved if thefeatures are made small compared to the thermal diffusion length for theheating process of interest. This rule can be applied to any features inthe heatsink plate, including those introduced to simplify loading orunloading of the wafer or the plate. It also can apply to any gapsbetween parts of any heatsink assembly that is pieced from sub-elements.It can also apply to the dimensions of protrusions 26 on the plate thatmay, for example, be used to provide stand-off features that set a gapbetween the wafer and the plate. We can also note that an approach offorming holes within the heatsink plate can also be used to optimize thethermal mass of the plate, and to affect its radiative properties.

Another issue that may be important arises from the tendency of thewafer or the plate to deform during thermal processing. The presence ofthe plate will affect this behaviour, and the design can be optimized totake account of the deformation behaviour. The use of a plate in closeproximity to the wafer may reduce the tendency of the wafer to deform asa result of the thermal stresses generated during the heating process.The plate design can even be optimized to reduce deformation, forexample by selecting a material that is relatively stiff or making theplate relatively thick. Other features can be used to determine theflexibility of the plate, such as ribs, recesses, protrusions or slits.Of course, the nature and dimensions such features would have to beoptimized in conjunction with the thermal operation of the plate. Forexample, they can be made smaller than the thermal diffusion lengthassociated with the process of interest, so that they do not degrade theuniformity of the thermal processing.

The heatsink plate can be constructed of a variety of materials, and itsphysical, thermal and optical properties can be optimized. Oneconvenient choice for the plate is silicon, on account of its closematch to the wafers properties, its good mechanical and thermalcharacteristics, and its high purity. The doping of the silicon can beselected to optimize the heat transfer characteristics. For example, theuse of heavily doped silicon, with a resistivity below 0.1 Ωcm, can beemployed in order to make the plate relatively opaque in the nearinfra-red, which may be useful if the plate's temperature is to bemonitored with a pyrometer operating at a wavelength greater than ˜1 μm.In contrast, if it is desirable to detect infra-red radiation thateither emanates from the wafer or is transmitted by the wafer, forexample to monitor the wafer temperature, then a lightly-doped siliconplate, with a resistivity greater than 0.1 μcm, which is transparent inthe near infra-red region, could be employed. However, other materialsmay also be used, such as silicon carbide, silicon dioxide, siliconnitride, aluminium oxide, sapphire, quartz, aluminium nitride, boronnitride, aluminium oxynitride, graphite, carbon, diamond, yttriumaluminium garnet (YAG) or other ceramic materials of high purity. Theplate may also be coated on any of its surfaces with layers that canenhance its properties. For example if the bulk material of the plate isnot believed to be of sufficient purity or chemical resistance to theprocessing ambient, then it may be coated with a layer that serves as abarrier to out gassing of impurities or to chemical attack.

Coatings and surface modifications may also serve to optimize thethermal or optical properties of the plate. For example, if a pyrometeris used for measuring the temperature of the plate, then it may beuseful to use a coating to form an antireflection layer for thewavelength of radiation that the pyrometer detects as a means forsensing temperature. This approach increases the emissivity of theplate, which can help to reduce errors in the temperature measurementthat arise from reflection of stray radiation into the pyrometer system,as well as helping to define a high value of emissivity, which increasesthe signal detected by the pyrometer and improves accuracy. Optimizationof the optical properties of the heatsink plate may also be useful inother ways. For example, the selection of the material and coatings canassist in defining the nature of the heating cycle. For example,selection of a material that is at least partially transparent to partof the radiation employed for heating would tend to reduce thetemperature it reaches during the heating cycle relative to that of thewafer, and hence improve cooling efficiency. Another example would be tochoose a material or a coating that increases the emissivity across therange of wavelength where the plate emits thermal radiation. This wouldincrease the efficiency of the radiative cooling and can accelerate thecooling rate.

Another aspect that may help operation of the plate in certainconditions is preparation of the surface that faces the wafer in amanner so that the thermal conduction into the plate is more efficient.Under some heat transfer conditions the transfer of heat through a gasto a surface can be sensitive to the surface texture. In this case, itmay be useful for that surface to be textured in a manner that improvesthe efficiency of heat transfer. Texturing may be performed by anyconventional method that forms grooves, protrusions, and the like.

It is appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed above. Rather, as set forth in the attached claims, the scopeof the present invention includes both combinations and sub-combinationsof various features discussed herein, along with such variations andmodifications as would occur to a person of skill in the art.

1-50. (canceled)
 51. A thermal processing method, comprising:positioning an object in a thermal processing chamber such that theobject is adjacent to a thermal transfer plate; pre-heating the object;and heating at least a first location on the object by directing atleast one pulse of energy toward the first location on the object for aduration of less than 1 second; wherein the the' Hal transfer plate hasa flexibility configured to reduce object deformation during the thermalprocessing of the object.
 52. The method of claim 51, wherein thethermal transfer plate has a first region and a second region, theflexibility of the thermal transfer plate at the first region beingdifferent than the flexibility of the thermal transfer plate at thesecond region.
 53. The method of claim 51, wherein the flexibility ofthe thermal transfer plate is optimized to reduce object deformationduring thermal processing of the object by configuring the stiffness ofthe thermal transfer plate.
 54. The method of claim 51, wherein theflexibility of the thermal transfer plate is optimized to reduce objectdeformation during the thermal processing of the object by configuringthe thickness of the thermal transfer plate.
 55. The method of claim 51,wherein the flexibility of the thermal transfer plate is configured toreduce object deformation by incorporating at least one discontinuity inthe thermal transfer plate.
 56. The method of claim 55, wherein thediscontinuity has a size that is less than a thermal diffusion lengthassociated with the thermal process.
 57. The method of claim 55, whereinthe discontinuity comprises at least one of a slit, a rib, a recess, aprotrusion, or a hole.
 58. The method of claim 55, wherein thediscontinuity has a dimension of about 2 mm or less.
 59. The method ofclaim 51, wherein heating the object comprises scanning the surface ofthe object with a laser.
 60. The method of claim 51, wherein heating theobject comprises illuminating the object with at least one lamp.
 61. Themethod of claim 51, wherein the thermal transfer plate is positionedsuch that the plate and a surface of the object are approximatelyparallel to one another and define a gap.
 62. The method of claim 61,wherein the gap is partially bridged by at least one of an offset or aprotrusion.
 63. The method of claim 61, wherein the distance of a firstportion of the thermal transfer plate from the object is less than thedistance of a second portion of the thermal transfer plate from theobject.
 64. The method of claim 61, wherein the method comprisesdelivering a gas into the gap.
 65. A system for thermal treatment of anobject within a chamber, comprising: a heating arrangement configured todirect a pulse of energy towards a surface of an object; and a thermaltransfer plate positioned adjacent to the object, the thermal transferplate having a flexibility that is configured to reduce objectdeformation during thermal treatment of the object.
 66. The system ofclaim 65, wherein the thermal transfer plate has a first region and asecond region, the flexibility of the thermal transfer plate at thefirst region being different than the flexibility of the thermaltransfer plate at the second region.
 67. The system of claim 65, whereinthe thermal transfer plate has a stiffness that is optimized to reduceobject deformation during thermal treatment of the object.
 68. Thesystem of claim 65, wherein the thermal transfer plate has a thicknessthat is optimized to reduce object deformation during thermal treatmentof the object.
 69. The system of claim 65, wherein the thermal transferplate comprises at least one discontinuity in the thermal transferplate.
 70. The system of claim 69, wherein the discontinuity has a sizethat is less than a thermal diffusion length associated with the thermalprocess.
 71. The system of claim 69, wherein the discontinuity comprisesat least one of a slit, a rib, a recess, a protrusion, or a hole. 72.The system of claim 69, wherein the discontinuity has a dimension ofabout 2 mm or less.
 73. The system of claim 65, wherein the thermaltransfer plate and the object are separated by a gap.
 74. The system ofclaim 73, wherein the gap is partially bridged by at least one of anoffset or a protrusion.
 75. The system of claim 73, wherein the distanceof a first portion of the thermal transfer plate from the object is lessthan the distance of a second portion of the thermal transfer plate fromthe object.
 76. The system of claim 73, wherein the gap is filled with agas.
 77. A method, comprising: preparing a thermal transfer plate foruse in a thermal processing chamber used for thermally treating anobject, the thermal transfer plate configured to be positioned adjacentto the object, the thermal processing chamber configured to direct atleast one pulse of energy toward the object for a duration of less than1 second; adjusting the flexibility of the thermal transfer plate toreduce object deformation during thermal treatment of the object. 78.The method of claim 77, wherein adjusting the flexibility of the thermaltransfer plate comprises adjusting the stiffness of the material used toconstruct the thermal transfer plate.
 79. The method of claim 77,wherein adjusting the flexibility of the thermal transfer platecomprises adjusting the thickness of the thermal transfer plate.
 80. Themethod of claim 77, wherein adjusting the flexibility of the thermaltransfer plate comprises incorporating a discontinuity in thermaltransfer plate.
 81. The method of claim 80, wherein the discontinuityhas a size that is less than a thermal diffusion length associated withthe object.
 82. The method of claim 80, wherein the discontinuitycomprises at least one of a slit, a rib, a recess, a protrusion, or ahole.
 83. The method of claim 80, wherein the discontinuity has adimension of about 2 mm or less.